Adjusting the step of a UI element
The step sizes for properties are programmed in and not easily user adjustable.

While clicking the arrows will always step in the same amount there are a couple of keys that can help if you drag the value instead of clicking each arrow. Holding shift while dragging will step in smaller sizes, Alt smaller again (generally half of shift steps) and together even slower.

These adjustments are dynamic, so you can start dragging the value to get close, then hold shift to slow it down to get the final value.